Wing air slot



E. H. POLK WING AIR SLOT April 6, 1948.

Filed June 11, 1943 INVENTOR ATTORNEY Patented Apr. 6, 1948 UNITEDSTATES F F I EK 2,43 94g l 3 1 a WING AIR SLOT Edwin H. Polk, United.States Navy Application June 11, 1943, Serial No. 490 431 2 Claims.(crane-4m (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370

The subject matter of this invention is a means for increasing thelateral stability of an airplane, and more generally for improving thecontrol re sponse of the several airplane control surfaces at reducedflying speeds,

It is well known that the controls in an airplane become sloppy at lowflying speeds, particularly when the air speed approaches stallingspeed. Especially is this true of the aileron controls, because normallythey do not get the benefit of the airstream from the propeller, whichis usually mounted on or near the axis of the plane, whereas theailerons are necessarily located at some distance outboard therefrom.

One of the objects of the present invention is to direct some of the aircurrents from the propeller airstream outboardly toward the tips of thewings and emit them in the proximity of the ailerons. This and othermore specific objects will appear in the following description which isaccompanied by the drawing, in which:

Fig. 1 shows a typical airplane wing in plan view, with one form of themeans for diverting part of the airstream of the propeller toward theaileron,

Fig. 2 is a front view of the same wing, and

Fig. 3 is a section thereof taken at 3-3 of Fig. 1. Referring to thedrawing in which a preferred form of the invention is shown, Irepresents the wing, 2 its leadin edge, 3 the aileron and t the air ductthrough the wing, the inlet end of which opens at the leading edge at 5,which is within the area of the propeller airstream, the outer edge ofwhich is approximately indicated by the dot and dash line 6 (Fig. 1).The outlet l I of the air duct constitutes a chamber l2, th'e reverselyand inwardly curved contraction l3 thereof having acontinuously'tapering top and bottom contour l4 up to the place ofconnection with a narrow slot 1 in the upper surface of the wing alongthe front of the aileron. This construction forms an outlet nozzle l5which is slanted in a direction so as to effect the aileron controls,The wing is shown diagrammatically in the figures and may be constructedin any of the usual forms. It may be of any other shape and dimensionsbesides that shown here for the purpose of illustration.

Generally the wing will have longitudinal structural beams 9 and it.Preferably the slot l in the upper wing surface will be placed forwardof the after beam It, as shown, thereby rendering it unnecessary topierce the beam to accommodate the air supply duct nor to redesign it tostrengthen it at the point of piercing.

The result of diverting a portion of the airstream from the area of thepropeller airstream by means of the air duct shown, or any other form ofconduit, to the proximity of the aileron, is that the loss of thelateral stability, as the air speed decreases, is delayed, until a lowerair speed is reached than would be the case without the provision ofthis airstream diverting means. Thus the effectiveness of the aileroncontrol is actually increased, particularly at the lower speeds.Normally the wings near the tips tend to stall out at the slower speeds,and it is to delay this stalling action that the slots are placed in theupper wing surfaces so as to emit the air in the direction of theailerons and thus delay this action. The action may be further delayedto a. certain extent by some slots formed in the wing immediately infront of the forward edge of the aileron, as shown at 8 in Fig. 3, so asto divert some of the air from the under side of the wing up through thewing to the top. over the aileron.

Although only the preferred form of the air ducts and slots is shown,many other arrangements may be used whereby to divert the air from thepropeller airstream or some other locations of a higher air speed to theproximity of the control surfaces where the airstream may be much lowerat the time when stalling speed is approached.

This invention may be used by or for the Government of the United Statesfor governmental purposes without the payment to me of any royaltythereon or therefor.

What is claimed is:

1. An airplane wing having improved aileron response at low airspeeds,with fore and aft longitudinal beam members tapering toward the outerend of the wing, an aileron hingedto the trailing edge of said wing atits outer end, a slot in the upper surface of the wing ahead of the aftbeam member opposite said aileron, a rearwardly directed passage in saidwing connected to said slot, an air passage in the propeller slip streamextending from the leading edge of the wing through the thick portion ofthe fore beam member, and an air conduit from said last named passage tosaid rearwardly directed passage,

whereby the thinner portion of the aft beam member is not weakened byany passages for the air directed toward the aileron.

2. An airplane wing comprisin a hollow airfoil having a slot extendingalong a portion of the trailing edge of the airfoil and substantiallyparallel thereto, means defining an air duct embodled in the airfoil andhaving an opening confined 3 to and directed through said leading edgeto provide an inlet to the air duct, a chamber in the airfoil branchingfrom the air duct to form an outletand being connected with the slot,said chamber being as broad as the slot and having a 113- I ;versely andinwardly curved contraction where it branches from the air duct, merginginto a continuously tapering top and bottom contour up to the place ofconnection with the slot to form an outlet nozzle, and a separateairfoil mounted conr tiguously to the slot and located within the sub-''stantiai confines 01' the wing.

EDWIN H. POLK.

REFERENCES CITED The following references are of record in th NumberNumber file of this patent: a

Great Britain Mar. 20, 1930

